Composite shielding film, electromagnetic shielding structure, and electronic device

Abstract

A composite shielding film, an electromagnetic shielding structure, and an electronic device, relating to the technical field of electronics. The composite shielding film comprises: a first conductive layer, a second conductive layer, and a conductive structure. The first conductive layer and the second conductive layer are opposite to each other and are spaced from each other. An orthographic projection area of the second conductive layer on a reference plane parallel to the first conductive layer falls within an orthographic projection area of the first conductive layer on the reference plane. The electrical conductivity of the first conductive layer ranges from 2,000 Siemens per meter to 80,000 Siemens per meter. The electrical conductivity of the second conductive layer is greater than or equal to 1,000 Siemens per meter. For example, the electrical conductivity of the second conductive layer is greater than the electrical conductivity of the first conductive layer. The conductive structure is connected to the first conductive layer and the second conductive layer, and is used for grounding the first conductive layer and the second conductive layer. The composite shielding film can effectively shield electromagnetic wave signals and reduce electromagnetic wave signal leakage. The present application is used for shielding electromagnetic wave signals.

Description

Composite shielding film, electromagnetic shielding structure and electronic equipment

[0001] This application claims priority to Chinese patent application No. 202410033787.5 filed on January 9, 2024, entitled “Composite shielding film, electromagnetic shielding structure and electronic device”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of electronic technology, and in particular to a composite shielding film, an electromagnetic shielding structure and an electronic device. Background Art

[0003] With the popularization of electronic equipment and the rapid development of the electronic information industry, electromagnetic wave technology has been widely used in many technical fields.

[0004] Electronic devices often contain components that emit additional electromagnetic signals during operation (such as mobile phone system-on-chips (SOCs) and fast-charging modules). These additional electromagnetic signal sources are prone to leakage, which can lead to information leakage, interfere with the normal operation of electronic devices, and even endanger human health.

[0005] Therefore, it is necessary to shield electromagnetic wave signals to reduce electromagnetic wave signal leakage.

[0006] Summary of the Invention

[0007] The present application provides a composite shielding film, an electromagnetic shielding structure, and an electronic device. The composite shielding film can shield electromagnetic wave signals and reduce electromagnetic wave signal leakage. The solution provided in the present application is as follows.

[0008] In a first aspect, the present application provides a composite shielding film, comprising: a first conductive layer, a second conductive layer, and a conductive structure; wherein the first conductive layer and the second conductive layer are opposite and spaced apart from each other, and the orthographic projection area of ​​the second conductive layer on a reference plane parallel to the first conductive layer is located within the orthographic projection area of ​​the first conductive layer on the reference plane; the conductivity of the first conductive layer ranges from 2,000 Siemens per meter to 80,000 Siemens per meter, for example, the conductivity of the first conductive layer ranges from 20,000 Siemens per meter to 80,000 Siemens per meter, or from 30,000 Siemens per meter to 50,000 Siemens per meter. The conductivity of the second conductive layer is greater than or equal to 1,000 Siemens per meter; for example, the conductivity of the second conductive layer is greater than the conductivity of the first conductive layer. Optionally, the conductivity of the second conductive layer is greater than 100,000 Siemens per meter, or the conductivity of the second conductive layer is greater than 500,000 Siemens per meter, or the conductivity of the second conductive layer ranges from greater than 1,000,000 Siemens per meter. The conductive structure connects the first conductive layer and the second conductive layer and is used to ground the first conductive layer and the second conductive layer.

[0009] In an embodiment of the present application, when the conductive structure grounds the first conductive layer and the second conductive layer, if the conductivity of the first conductive layer is in the range of 2000 Siemens per meter (S / m) to 80000 S / m, and the conductivity of the second conductive layer is greater than or equal to 1000 S / m, then the electromagnetic wave signal transmitted to the second conductive layer will be reflected by the second conductive layer to the first conductive layer; and a portion of the electromagnetic wave signal transmitted to the first conductive layer will be lost and attenuated on the first conductive layer, and another portion of the electromagnetic wave signal transmitted to the first conductive layer will be reflected by the first conductive layer to the second conductive layer. This process repeats itself, and eventually the electromagnetic wave signal transmitted to the first conductive layer and / or the second conductive layer will be basically lost. Optionally, when the conductivity of the second conductive layer is within a certain range, the second conductive layer may also have the effect of losing and attenuating the electromagnetic wave signal.

[0010] According to the above analysis, the composite shielding film provided in the embodiment of the present application can effectively shield electromagnetic wave signals. This is due to the fact that the composite shielding film contains a double conductive layer (a first conductive layer and a second conductive layer) and a conductive structure. When the conductive structure grounds both layers of the double conductive layer, under the specific conductivity of the double conductive layer, the double conductive layer can converge most of the electromagnetic wave signals between the first conductive layer and the second conductive layer. At the same time, the conductivity of the first conductive layer is 2000S / m to 80000S / m, which can reduce the reflection of the electromagnetic wave signal and make the electromagnetic wave signal enter the first conductive layer for loss.

[0011] When the composite shielding film is used as a shielding cover in an electromagnetic shielding structure, the conductive structure in the composite shielding film can be connected to the grounding frame so that the first conductive layer and the second conductive layer are grounded through the conductive structure and the grounding frame. In this way, among the electromagnetic wave signals emitted by the electromagnetic wave signal source, a part of the electromagnetic wave signals will be shielded at the grounding frame and cannot be transmitted outside the grounding frame. Another part of the electromagnetic wave signals will be transmitted to the first conductive layer and / or the second conductive layer; after that, these electromagnetic wave signals will be basically lost on the first conductive layer under the action of the first conductive layer and the second conductive layer; in this way, the electromagnetic wave signals that are not shielded at the grounding frame will not be transmitted outside the electromagnetic shielding structure. It can be seen that under the action of the grounding frame and the composite shielding film provided in this application, the electromagnetic wave signals emitted by the electromagnetic wave signal source can be shielded.

[0012] In the above embodiment, the conductive structure is used to ground both the first conductive layer and the second conductive layer. It is understandable that the conductive structure can be implemented in various ways, and two of them will be used as examples for explanation.

[0013] 1. In a first possible implementation of a conductive structure, the conductive structure includes: a first conductor and a second conductor; the first conductor is located between and connects the first and second conductive layers; the second conductor is located on a side of the second conductive layer away from the first conductive layer and connects the second conductive layer, and the second conductor is used for grounding. When the composite shielding film is used in an electromagnetic shielding structure, the second conductor can be connected to a grounding frame to ground the second conductor, thereby achieving grounding of the first and second conductive layers.

[0014] 2. In a second possible implementation of the conductive structure, the conductive structure includes: a first conductor, a second conductor and a third conductor. The first conductor is located between the first conductive layer and the second conductive layer, and connects the first conductive layer and the second conductive layer. The second conductor is located on the side of the second conductive layer away from the first conductive layer, and is connected to the second conductive layer, and the second conductor is used for grounding. The third conductor is located on the side of the first conductive layer close to the second conductive layer, and the orthographic projection area of ​​the third conductor on the above-mentioned reference plane (a plane parallel to the first conductive layer) is located outside the orthographic projection area of ​​the second conductive layer on the reference plane; the third conductor is connected to the first conductive layer, and the third conductor is also used for grounding. When the composite shielding film is applied to the electromagnetic shielding structure, the second conductor and the third conductor can be connected to the grounding frame so that the second conductor and the third conductor are both grounded, thereby achieving grounding of the first conductive layer and the second conductive layer.

[0015] In this application, the conductive structure can be made of any conductive material (such as conductive adhesive, metal, conductive inorganic material, etc.). In this application, the conductive structure material includes conductive adhesive as an example. For example, the first conductor, the second conductor, and the third conductor can all be made of conductive adhesive.

[0016] Optionally, for electromagnetic wave signals between 300 MHz and 10 GHz (the frequency of the electromagnetic wave signal is between 300 MHz and 10 GHz), the relative complex permeability of the first conductive layer and / or the second conductive layer is greater than or equal to 1, for example, the relative complex permeability is 1, 10, etc. When the relative complex permeability of the first conductive layer is greater than or equal to 1 for electromagnetic wave signals between 300 MHz and 10 GHz, the first conductive layer can enhance its ability to attenuate and dissipate the electromagnetic wave signal transmitted to the first conductive layer, thereby improving the electromagnetic wave signal shielding effect. When the relative complex permeability of the second conductive layer is greater than or equal to 1 for electromagnetic wave signals between 300 MHz and 10 GHz, the second conductive layer can also attenuate and dissipate the electromagnetic wave signal transmitted to the second conductive layer. It is understood that for electromagnetic wave signals between 300 MHz and 10 GHz, the relative complex permeability of the first conductive layer may also be greater than 1, and the relative complex permeability of the second conductive layer may also be greater than 1. For electromagnetic wave signals between 300 MHz and 10 GHz, the relative complex permeability of the first conductive layer may also be less than 1, and the relative complex permeability of the second conductive layer may also be less than 1.

[0017] Optionally, the first conductive layer and / or the second conductive layer has a thickness ranging from 1 micron to 100 microns, which may or may not include 1 micron, or which may or may not include 100 microns.

[0018] Optionally, the thermal conductivity of the first conductive layer ranges from 1 watt per meter per Kelvin to 400 watts per meter per Kelvin; and / or the thermal conductivity of the second conductive layer is greater than or equal to 10 watts per meter per Kelvin. When the thermal conductivity of the first conductive layer ranges from 1 watt per meter per Kelvin to 400 watts per meter per Kelvin, the first conductive layer has better thermal conductivity; when the thermal conductivity of the second conductive layer is greater than or equal to 10 watts per meter per Kelvin, the second conductive layer has better thermal conductivity. In this way, the composite shielding film has a greater probability of having better thermal conductivity, which, when used as a shielding cover, facilitates heat dissipation from an electromagnetic wave signal source.

[0019] The above description uses the example of a composite shielding film including a single second conductive layer. Alternatively, the composite shielding film may include multiple second conductive layers, each spaced apart from the other in a plane parallel to the first conductive layer. Each of the multiple second conductive layers can refer to the second conductive layer described above and is not further described in this application.

[0020] Optionally, the composite shielding film further comprises: a first insulating layer and / or a second insulating layer; the first insulating layer is positioned between the first conductive layer and the second conductive layer; and the second insulating layer is positioned on a side of the second conductive layer away from the first conductive layer. It is understood that the composite shielding film may also not include the first insulating layer and / or the second insulating layer, and this application does not limit this. In this case, the first conductive layer and the second conductive layer remain spaced apart from each other, and when the composite shielding film is used in an electromagnetic shielding structure, the second conductive layer is also spaced apart from the electromagnetic wave signal source.

[0021] In the second aspect, the present application provides an electromagnetic shielding structure, comprising: a substrate, a grounding frame and an electromagnetic wave signal source, and a composite shielding film described in any design in the first aspect; the grounding frame is grounded, the grounding frame is located on the target surface of the substrate, and surrounds the target area of ​​the target surface; the composite shielding film is located on the side of the grounding frame away from the substrate, and the conductive structure in the composite shielding film is connected to the side of the grounding frame away from the substrate; the second conductive layer in the composite shielding film is located between the first conductive layer and the grounding frame; the orthographic projection area of ​​the target area on the reference plane is located within the orthographic projection area of ​​the second conductive layer on the reference plane; the electromagnetic wave signal source is located between the substrate and the composite shielding film, and is located in the target area, and is insulated from both the grounding frame and the composite shielding film.

[0022] In the present application, the first conductive layer and the second conductive layer are both grounded, the first conductive layer and the second conductive layer form a loop, and the conductivity of the first conductive layer ranges from 2000S / m to 80000S / m, and the conductivity of the second conductive layer is greater than or equal to 1000S / m. In this case, among the electromagnetic wave signals emitted by the electromagnetic wave signal source, a part of the electromagnetic wave signals will be shielded at the grounding frame and cannot be transmitted outside the grounding frame. Another part of the electromagnetic wave signals will be transmitted to the first conductive layer and / or the second conductive layer; after that, these electromagnetic wave signals will be basically lost on the first conductive layer under the action of the first conductive layer and the second conductive layer; in this way, the electromagnetic wave signals that are not shielded at the grounding frame will not be transmitted outside the electromagnetic shielding structure. It can be seen that under the action of the grounding frame and the composite shielding film, the electromagnetic wave signals emitted by the electromagnetic wave signal source can be shielded.

[0023] Optionally, the composite shielding film includes: multiple second conductive layers, the target surface has multiple target areas, and the electromagnetic shielding structure includes multiple electromagnetic wave signal sources; the multiple target areas correspond one-to-one to the multiple second conductive layers, and the orthographic projection area of ​​the target area on the reference plane is located within the orthographic projection area of ​​the corresponding second conductive layer on the reference plane; the multiple target areas correspond one-to-one to the multiple electromagnetic wave signal sources, and the electromagnetic wave signal sources are located in the corresponding target areas.

[0024] When the composite shielding film includes multiple second conductive layers, a portion of the electromagnetic wave signal emitted by the electromagnetic wave signal source corresponding to each second conductive layer is shielded at the ground frame, while the remaining portion of the electromagnetic wave signal is transmitted to the first conductive layer or the second conductive layer and, under the action of the first conductive layer and the second conductive layer, is substantially completely dissipated at the first conductive layer. Thus, when the composite shielding film includes multiple second conductive layers, the ground frame and the composite shielding film are capable of shielding the electromagnetic wave signals emitted by the multiple electromagnetic wave signal sources corresponding to the multiple second conductive layers.

[0025] Furthermore, the ground frame in the embodiments of the present application may be a closed frame or not. For example, when the ground frame is not closed, the ground frame has at least one opening connecting the target area and the outside of the ground frame in the extension direction of the substrate (parallel to the substrate). When the ground frame has the above-mentioned opening, the area on the target surface of the substrate where the opening is located can be used to set up other structures (such as chips, circuits, etc.) in addition to the ground frame, thereby increasing the usable area of ​​the target surface of the substrate. Moreover, although the ground frame has an opening, under the action of the composite shielding film, the electromagnetic wave signals that are not shielded at the ground frame are basically transmitted to the first conductive layer and / or second conductive layer of the composite shielding film, and are not transmitted to the outside of the electromagnetic shielding structure from the opening in large quantities. It can be seen that the opening of the ground frame does not have a significant impact on the electromagnetic shielding function of the electromagnetic shielding structure. If the shielding cover is made of nickel silver as used in the related art, then when the ground frame has the above-mentioned opening, a large amount of electromagnetic wave signals will be transmitted from the opening to the outside of the electromagnetic shielding structure, thereby failing to achieve the electromagnetic shielding function of the electromagnetic shielding structure.

[0026] In a third aspect, the present application provides an electronic device, comprising: the electromagnetic shielding structure described in any design in the second aspect.

[0027] Optionally, the electronic device is a terminal device, such as a mobile phone, tablet computer, laptop computer, wearable device (such as smart watch, smart glasses, etc.), car, desktop computer. The electronic device may also not be a terminal device, for example, the electronic device is a network device (such as a gateway, router, server, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0028] FIG1 is a schematic structural diagram of a first composite shielding film provided in an embodiment of the present application;

[0029] FIG2 is a diagram showing the positional relationship between a surface of a second conductive layer close to a first conductive layer and a first conductor provided by an embodiment of the present application;

[0030] FIG3 is a diagram showing the positional relationship between a surface of a second conductive layer away from a first conductive layer and a second conductor provided by an embodiment of the present application;

[0031] FIG4 is a schematic structural diagram of a second composite shielding film provided in an embodiment of the present application;

[0032] FIG5 is a diagram showing the positional relationship between a surface of a first conductive layer close to a second conductive layer and a first conductor and a third conductor provided by an embodiment of the present application;

[0033] FIG6 is a schematic structural diagram of a third composite shielding film provided in an embodiment of the present application;

[0034] FIG7 is a schematic structural diagram of a fourth composite shielding film provided in an embodiment of the present application;

[0035] FIG8 is a schematic structural diagram of a fifth composite shielding film provided in an embodiment of the present application;

[0036] FIG9 is a schematic structural diagram of a sixth composite shielding film provided in an embodiment of the present application;

[0037] FIG10 is a schematic structural diagram of a seventh composite shielding film provided in an embodiment of the present application;

[0038] FIG11 is a schematic structural diagram of an eighth composite shielding film provided in an embodiment of the present application;

[0039] FIG12 is a schematic structural diagram of a ninth composite shielding film provided in an embodiment of the present application;

[0040] FIG13 is a schematic diagram of an electromagnetic shielding structure provided in an embodiment of the present application;

[0041] FIG14 is a schematic diagram of another electromagnetic shielding structure provided in an embodiment of the present application;

[0042] FIG15 is a schematic diagram of a closed grounding frame provided in an embodiment of the present application;

[0043] FIG16 is a schematic diagram of an unenclosed grounding frame provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The present application provides a composite shielding film, which is used in an electromagnetic shielding structure in an electronic device to shield electromagnetic wave signals emitted by an electromagnetic wave signal source in the electromagnetic shielding structure and reduce leakage of the electromagnetic wave signals.

[0045] The electronic device in this application can be a terminal device, such as a mobile phone, tablet computer, laptop computer, wearable device (such as smart watch, smart glasses, etc.), automobile, desktop computer. The electronic device can also be other than a terminal device, for example, the electronic device is a network device (such as a gateway, router, server, etc.).

[0046] Electronic devices include an electromagnetic signal source capable of emitting electromagnetic signals. This electromagnetic signal source can be composed of one or more chips, one or more circuits, or one or more electronic components. Leakage of the electromagnetic signals emitted by this source can lead to information leakage and even harm human health. Therefore, it is necessary to shield these electromagnetic signals, confining them to a specific space to reduce leakage.

[0047] In related art, electromagnetic wave signals are shielded by a substrate, a grounding frame, and a shielding cover. The grounding frame is fixed to the substrate, and the shielding cover is fixed to the side of the grounding frame away from the substrate. The shielding cover, grounding frame, and substrate form a closed space. An electromagnetic wave signal source is fixed to the substrate and located within this closed space. The shielding cover, grounding frame, and substrate are all made of metal materials, and these metal materials are all conductive and grounded through the grounding frame. This allows the electromagnetic wave signals emitted by the electromagnetic wave signal source located within the closed space formed by the shielding cover, grounding frame, and substrate to be shielded within this closed space, reducing electromagnetic wave signal leakage.

[0048] However, current shielding covers are made of a single material (nickel-nickel alloy, a copper alloy) and have a relatively simple structure. Furthermore, the thickness and weight of nickel-nickel alloy shielding covers are relatively large, resulting in a large volume and weight for the electronic device housing the substrate, ground frame, shielding cover, and electromagnetic wave signal source. The development trend of electronic devices (especially terminal devices) is towards miniaturization and lightweighting. Therefore, the large volume and weight of electronic devices are inconsistent with this development trend.

[0049] Furthermore, to ensure effective electromagnetic wave shielding, the shielding cover in related art must be strictly grounded. Therefore, all locations around the shielding cover must be connected to a ground frame. However, this results in a larger ground frame, which occupies a larger area on the substrate. This reduces the area available for arranging other components on the substrate, resulting in a smaller usable area on the substrate.

[0050] Therefore, how to reduce the weight and volume of the shielding materials and reduce the area occupied by the ground frame in the substrate has become a difficult problem in this field.

[0051] This application provides a composite shielding film that can be used as a shielding cover. Unlike related art shielding covers made of a single material, nickel silver, this composite shielding film can enrich the structure of the shielding cover. Furthermore, in some embodiments, the composite shielding film has a relatively low thickness and weight, which can reduce the volume and weight of the entire electronic device, conforming to the trend of miniaturization and lightweight electronic devices.

[0052] In addition, in some embodiments, the grounding frame in the electromagnetic shielding structure in which the composite shielding membrane provided by the present application is located may also have an opening, thereby reducing the area occupied by the grounding frame on the substrate, thereby increasing the area of ​​the substrate used to set up other components other than the grounding frame. Moreover, when the grounding frame has an opening, a good electromagnetic shielding effect can also be ensured by the composite shielding membrane. After testing, in some cases, the thermal conductivity of the composite shielding membrane provided by the embodiments of the present application is also good. When the composite shielding membrane is used as a shielding cover, it is beneficial to the heat dissipation of the electromagnetic wave signal source.

[0053] The composite shielding film provided in this application, the electromagnetic shielding structure in which the composite shielding film is located, and the electronic device will be introduced and explained below.

[0054] For example, FIG1 is a schematic structural diagram of a composite shielding film provided in an embodiment of the present application. As shown in FIG1 , the composite shielding film includes: a first conductive layer 001 , a second conductive layer 002 and a conductive structure 003 ;

[0055] The first conductive layer 001 and the second conductive layer 002 are disposed opposite to each other. In other words, the first conductive layer 001 and the second conductive layer 002 are parallel to each other and arranged in a direction perpendicular to the first conductive layer 001 .

[0056] The orthographic projection area of ​​the second conductive layer 002 on a reference plane C parallel to the first conductive layer 001 is located within the orthographic projection area of ​​the first conductive layer 001 on the reference plane C. This indicates that the area of ​​the first conductive layer 001 is larger, while the area of ​​the second conductive layer 002 is smaller; alternatively, the area of ​​the first conductive layer 001 is the same as the area of ​​the second conductive layer 002. Figure 1 takes the example of the case where the orthographic projection area of ​​the first conductive layer 001 on the reference plane C and the orthographic projection area of ​​the second conductive layer 002 on the reference plane C overlap and are both region Q1.

[0057] The conductivity of the first conductive layer 001 ranges from 2000 Siemens per meter (S / m) to 80,000 Siemens per meter. This range may or may not include 2000 S / m; this range may or may not include 80,000 S / m. For example, assuming the conductivity of the first conductive layer 001 is X, then 2000 S / m ≤ X ≤ 80,000 S / m, or 2000 S / m < X ≤ 80,000 S / m, or 2000 S / m ≤ X < 80,000 S / m, or 2000 S / m < X < 80,000 S / m. The conductivity of the second conductive layer 002 is greater than or equal to 1000 Siemens per meter. The conductivity of the second conductive layer 002 may also be greater than 1000 S / m.

[0058] For example, the conductivity of the first conductive layer 001 can be 2000 S / m, 10000 S / m, 20000 S / m, 80000 S / m, etc., and the conductivity of the second conductive layer 002 can be 1000 S / m, 1×10 6 S / m, 4×10 6 S / m, 3×10 6 S / m, etc.

[0059] Optionally, the range of the conductivity of the first conductive layer 001 may not be 2000 S / m to 80000 S / m. For example, the range of the conductivity of the first conductive layer may be 20,000 S / m to 80,000 S / m, or 30,000 S / m to 50,000 S / m, or 30,000 S / m to 80,000 S / m, or 20,000 S / m to 50,000 S / m, or 40,000 S / m to 50,000 S / m, etc. This embodiment of the present application is not limited to this.

[0060] When the conductivity of the first conductive layer is in the range of 20,000 S / m to 80,000 S / m, the conductivity of the first conductive layer may be 30,000 S / m, 40,000 S / m, or 50,000 S / m, etc. When the conductivity of the first conductive layer is in the range of 30,000 S / m to 50,000 S / m, the conductivity of the first conductive layer may be 40,000 S / m or 45,000 S / m, etc. When the conductivity of the first conductive layer is in the range of 30,000 S / m to 80,000 S / m, the conductivity of the first conductive layer may be 50,000 S / m or 60,000 S / m, etc. When the conductivity of the first conductive layer is in the range of 20,000 S / m to 50,000 S / m, the conductivity of the first conductive layer may be 30,000 S / m or 40,000 S / m, etc. When the conductivity of the first conductive layer is in the range of 40,000 S / m to 50,000 S / m, the conductivity of the first conductive layer may be 45,000 S / m or 46,000 S / m, etc.

[0061] Optionally, the conductivity of the second conductive layer 002 is greater than the conductivity of the first conductive layer 001. For example, the conductivity of the second conductive layer 002 is greater than 100,000 Siemens per meter, or greater than 500,000 Siemens per meter, or the conductivity of the second conductive layer 002 is greater than 1,000,000 Siemens per meter.

[0062] When the conductivity of the second conductive layer is greater than 100,000 S / m, the conductivity of the second conductive layer may be 110,000 S / m, 120,000 S / m, or 130,000 S / m, etc. When the conductivity of the second conductive layer is greater than 500,000 S / m, the conductivity of the second conductive layer may be 600,000 S / m, 700,000 S / m, or 800,000 S / m, etc. When the conductivity of the second conductive layer is greater than 1,000,000 S / m, the conductivity of the second conductive layer may be 1,100,000 S / m, 1,200,000 S / m, or 1,300,000 S / m, etc. In the embodiment of the present application, the conductivity of the second conductive layer 002 may also be less than or equal to the conductivity of the first conductive layer 001. For example, the conductivity of the second conductive layer 002 may be greater than 1,000 S / s and less than 2,000 S / m, which is not limited in the embodiment of the present application.

[0063] Conductive structure 003 connects first conductive layer 001 and second conductive layer 002 and is used to ground first conductive layer 001 and second conductive layer 002. For example, in FIG1 , first conductor 0031 in conductive structure 003 connects first conductive layer 001 and second conductive layer 002 and is used to ground both first conductive layer 001 and second conductive layer 002; second conductor 0032 in conductive structure 003 connects second conductive layer 002 and is grounded and is used to ground first conductive layer 001 and second conductive layer 002.

[0064] In the embodiment of the present application, when the conductive structure 003 grounds the first conductive layer 001 and the second conductive layer 002, if the conductivity of the first conductive layer 001 is in the range of 2000 S / m to 80000 S / m and the conductivity of the second conductive layer 002 is greater than or equal to 1000 S / m, the electromagnetic wave signal transmitted to the second conductive layer 002 will be reflected by the second conductive layer 002 to the first conductive layer 001; in addition, a portion of the electromagnetic wave signal transmitted to the first conductive layer 001 will be lost and attenuated on the first conductive layer 001, and another portion of the electromagnetic wave signal transmitted to the first conductive layer 001 will be reflected by the first conductive layer 001 to the second conductive layer 002. This process repeats, and eventually, the electromagnetic wave signal transmitted to the first conductive layer 001 and / or the second conductive layer 002 will be substantially completely lost. Optionally, when the conductivity of the second conductive layer 002 is within a certain range, the second conductive layer 002 may also have the effect of losing and attenuating the electromagnetic wave signal.

[0065] According to the above analysis, the composite shielding film provided in the embodiment of the present application can effectively shield electromagnetic wave signals. This is due to the fact that the composite shielding film contains a double conductive layer (a first conductive layer and a second conductive layer) and a conductive structure. When the conductive structure grounds both layers of the double conductive layer, under the specific conductivity of the double conductive layer, the double conductive layer can converge most of the electromagnetic wave signals between the first conductive layer and the second conductive layer. At the same time, the conductivity of the first conductive layer is 2000S / m to 80000S / m, which can reduce the reflection of the electromagnetic wave signal and make the electromagnetic wave signal enter the first conductive layer for loss.

[0066] When the composite shielding film is used as a shielding cover in an electromagnetic shielding structure, the conductive structure 003 in the composite shielding film can be connected to the grounding frame so that the first conductive layer 001 and the second conductive layer 002 are grounded through the conductive structure 003 and the grounding frame. In this way, among the electromagnetic wave signals emitted by the electromagnetic wave signal source, a part of the electromagnetic wave signals will be shielded at the grounding frame and cannot be transmitted outside the grounding frame. Another part of the electromagnetic wave signals will be transmitted to the first conductive layer 001 and / or the second conductive layer 002; after that, these electromagnetic wave signals will be basically lost on the first conductive layer 001 under the action of the first conductive layer 001 and the second conductive layer 002; in this way, the electromagnetic wave signals that are not shielded at the grounding frame will not be transmitted outside the electromagnetic shielding structure. It can be seen that under the action of the grounding frame and the composite shielding film provided in this application, the electromagnetic wave signals emitted by the electromagnetic wave signal source can be shielded.

[0067] Optionally, for electromagnetic wave signals in the range of 300 MHz to 10 GHz (the frequency of the electromagnetic wave signal is 300 MHz to 10 GHz), the relative complex permeability of the first conductive layer 001 and / or the second conductive layer 002 is greater than or equal to 1, for example, the relative complex permeability is 1, 10, etc. When the relative complex permeability of the first conductive layer 001 is greater than or equal to 1 for electromagnetic wave signals in the range of 300 MHz to 10 GHz, the first conductive layer 001 can enhance its ability to attenuate and dissipate the electromagnetic wave signal transmitted to the first conductive layer 001, thereby improving the electromagnetic wave signal shielding effect. When the relative complex permeability of the second conductive layer 002 is greater than or equal to 1 for electromagnetic wave signals in the range of 300 MHz to 10 GHz, the second conductive layer 002 can also attenuate and dissipate the electromagnetic wave signal transmitted to the second conductive layer 002. It is understandable that, for electromagnetic wave signals between 300 MHz and 10 GHz, the relative complex permeability of the first conductive layer 001 may be greater than 1, and the relative complex permeability of the second conductive layer 002 may be greater than 1. For electromagnetic wave signals between 300 MHz and 10 GHz, the relative complex permeability of the first conductive layer 001 may be less than 1, and the relative complex permeability of the second conductive layer 002 may be less than 1.

[0068] In the above embodiment, the conductive structure 003 is used to ground both the first conductive layer 001 and the second conductive layer 002. It is understandable that the conductive structure 003 can be implemented in various ways, and two of them will be used as examples for explanation.

[0069] 1. In a first possible implementation of conductive structure 003, referring to Figure 1 , conductive structure 003 includes a first conductor 0031 and a second conductor 0032. First conductor 0031 is located between and connects first conductive layer 001 and second conductive layer 002. Second conductor 0032 is located on a side of second conductive layer 001 away from first conductive layer 001 and connects second conductive layer 002. Second conductor 0032 is used for grounding. When the composite shielding film is used in an electromagnetic shielding structure, second conductor 0032 can be connected to a grounding frame to ground second conductor 0032, thereby achieving grounding of first conductive layer 001 and second conductive layer 002.

[0070] The first conductor 0031 may be connected to an edge region of the surface of the first conductive layer 001 close to the second conductive layer 002 (taken as an example in FIG. 1 ), or the first conductor 0031 may be connected to a non-edge region of the surface of the first conductive layer 001 close to the second conductive layer 002 .

[0071] The first conductor 0031 may be connected to an edge region of the surface of the second conductive layer 002 close to the first conductive layer 001 (taken as an example in FIG. 1 ), or the first conductor 0031 may be connected to a non-edge region of the surface of the second conductive layer 002 close to the first conductive layer 001 .

[0072] The second conductor 0032 may be connected to an edge region of the surface of the second conductive layer 002 away from the first conductive layer 001 (taken as an example in FIG. 1 ), or the second conductor 0032 may be connected to a non-edge region of the surface of the second conductive layer 002 away from the first conductive layer 001 .

[0073] For example, FIG2 is a positional relationship diagram between a surface of a second conductive layer 002 close to the first conductive layer 001 and a first conductor 0031 provided in an embodiment of the present application. The structure shown in FIG1 includes the structure at section AA in FIG2. As shown in FIG2, when the first conductor 0031 is connected to the edge area of ​​the surface of the second conductive layer 002 close to the first conductive layer 001, the edge area is annular (square ring, circular ring or irregular ring), and the first conductor 0031 can also be annular, and the orthographic projection area of ​​the first conductor 0031 on the surface surrounds the central area surrounded by the edge area. The orthographic projection area of ​​the first conductor 0031 on the surface is located in the edge area, for example, the orthographic projection area of ​​the first conductor 0031 on the surface is the edge area. It can be understood that when the first conductor 0031 is connected to the edge area of ​​the surface of the second conductive layer 002 close to the first conductive layer 001, the first conductor 0031 can also be non-annular, for example, the first conductor 0031 is semi-annular, strip-shaped, irregularly shaped, etc., and the embodiment of the present application is not limited to this.

[0074] As another example, FIG3 is a positional relationship diagram between a surface of a second conductive layer 002 away from the first conductive layer 001 and a second conductor 0032 provided in an embodiment of the present application. The structure shown in FIG1 includes the structure of section BB in FIG3. As shown in FIG3, when the second conductor 0032 is connected to the edge area of ​​the surface of the second conductive layer 002 away from the first conductive layer 001, the edge area is annular (square ring, circular ring or irregular ring). The second conductor 0032 can also be annular, and the orthographic projection area of ​​the second conductor 0032 on the surface surrounds the central area surrounded by the edge area. The orthographic projection area of ​​the second conductor 0032 on the surface is located in the edge area. For example, the orthographic projection area of ​​the second conductor 0032 on the surface is the edge area. It is understandable that when the second conductor 0032 is connected to the edge area of ​​the surface of the second conductive layer 002 away from the first conductive layer 001, the second conductor 0032 can also be non-annular. For example, the second conductor 0032 is semi-annular, strip-shaped, irregular, etc., and this embodiment of the present application is not limited to this.

[0075] 2. In a second possible implementation of conductive structure 003, referring to FIG4 , conductive structure 003 includes a first conductor 0031, a second conductor 0032, and a third conductor 0033. First conductor 0031 is located between first conductive layer 001 and second conductive layer 002, connecting first conductive layer 001 and second conductive layer 002. Second conductor 0032 is located on a side of second conductive layer 001 away from first conductive layer 001 and connected to second conductive layer 002. Second conductor 0032 is used for grounding. Third conductor 0033 is located on a side of first conductive layer 001 closer to second conductive layer 002, and an orthographic projection area Q3 of third conductor 0033 on reference plane C (a plane parallel to first conductive layer 001) is located outside an orthographic projection area Q2 of second conductive layer 002 on reference plane C. Third conductor 0033 is connected to first conductive layer 001 and also serves as grounding. When the composite shielding film is applied in an electromagnetic shielding structure, the second conductor 0032 and the third conductor 0033 can be connected to the grounding frame so that the second conductor 0032 and the third conductor 0033 are both grounded, thereby achieving grounding of the first conductive layer 001 and the second conductive layer 002.

[0076] In this second possible implementation, the first conductor 0031 and the third conductor 0033 can be combined into one conductor (referred to as the fourth conductor), a portion of the fourth conductor (the first conductor 0031) being located between the first conductive layer 001 and the second conductive layer 002, and connecting the first conductive layer 001 and the second conductive layer 002; another portion of the fourth conductor (the third conductor 0033) being located on a side of the first conductive layer 001 close to the second conductive layer 002, and an orthographic projection area Q3 of the other portion on the above-mentioned reference plane C being located outside an orthographic projection area Q2 of the second conductive layer 002 on the reference plane C; the other portion being connected to the first conductive layer 001, and the other portion being also used for grounding.

[0077] In this second implementation, the area of ​​the orthographic projection Q1 of the first conductive layer 001 on the reference plane is greater than the area of ​​the orthographic projection Q2 of the second conductive layer 002 on the reference plane. This allows a portion of the first conductive layer 001 to protrude from the second conductive layer 002, and the third conductor 0033 can be connected to the surface of this portion near the second conductive layer 002. The surface of the portion of the first conductive layer 001 that does not protrude from the second conductive layer 002 near the second conductive layer 002 can be connected to the first conductor 0031.

[0078] The first conductor 0031 and the third conductor 0033 are respectively connected to different areas of the surface of the first conductive layer 001 near the second conductive layer 002. The first conductor 0031 and the third conductor 0033 may or may not be connected. In the embodiment of the present application, the connection between the first conductor 0031 and the third conductor 0033 is used as an example. Alternatively, the first conductor 0031 and the third conductor 0033 may be connected as a single piece.

[0079] The first conductor 0031 may be connected to an edge region of the surface of the first conductive layer 001 close to the second conductive layer 002 (taken as an example in FIG. 1 ), or the first conductor 0031 may be connected to a non-edge region of the surface of the first conductive layer 001 close to the second conductive layer 002 .

[0080] The first conductor 0031 may be connected to an edge region of the surface of the second conductive layer 002 close to the first conductive layer 001 (taken as an example in FIG. 4 ), or the first conductor 0031 may be connected to a non-edge region of the surface of the second conductive layer 002 close to the first conductive layer 001 .

[0081] The second conductor 0032 may be connected to an edge region of the surface of the second conductive layer 002 away from the first conductive layer 001 (taken as an example in FIG. 4 ), or the second conductor 0032 may be connected to a non-edge region of the surface of the second conductive layer 002 away from the first conductive layer 001 .

[0082] The third conductor 0033 may be connected to an edge region of the surface of the first conductive layer 001 close to the second conductive layer 002 (taken as an example in FIG. 4 ), or the third conductor 0033 may be connected to a non-edge region of the surface of the first conductive layer 001 close to the second conductive layer 002 .

[0083] For example, FIG5 is a positional relationship diagram between a surface of a first conductive layer 001 on the side close to the second conductive layer 002 and a first conductor 0031 and a third conductor 0033 provided in an embodiment of the present application. The structure shown in FIG4 includes the structure of section CC in FIG5. As shown in FIG5, when the first conductor 0031 and the third conductor 0033 are both connected to the edge area of ​​the surface of the first conductive layer 001 on the side close to the second conductive layer 002, the edge area is annular (square ring, circular ring or irregular ring, FIG5 takes a square ring as an example), and the integral part formed by connecting the first conductor 0031 and the third conductor 0033 can also be annular, and the orthographic projection area of ​​the integral part on the surface surrounds the central area surrounded by the edge area. The orthographic projection area of ​​the integral part on the surface is located in the edge area. For example, the orthographic projection area of ​​the integral part on the surface is the edge area. It is understandable that the integrated part may not be ring-shaped, for example, the integrated part may be semi-ring-shaped, strip-shaped, irregularly shaped, etc. In addition, the first conductor 0031 and the third conductor 0033 may not be connected, and this embodiment of the application does not limit this.

[0084] As another example, the positional relationship diagram between the surface of the second conductive layer 002 away from the first conductive layer 001 and the second conductor 0032 can refer to FIG. 3 , which is not described in detail in this embodiment of the present application.

[0085] In the above embodiment, the conductive structure 003 includes a conductor (such as the first conductor) that simultaneously connects the first conductive layer 001 and the second conductive layer 002. The conductive structure 003 electrically connects the first conductive layer 001 and the second conductive layer 002 through this conductor, and then grounds the second conductive layer 002 through another conductor (such as the second conductor or the third conductor), thereby grounding the first conductive layer 001 and the second conductive layer 002. It is understood that the conductive structure 003 may not include a conductor that simultaneously connects the first conductive layer 001 and the second conductive layer 002.

[0086] For example, as shown in Figure 6, conductive structure 003 includes the aforementioned second conductor 0032 and third conductor 0033, but does not include the aforementioned first conductor. In this case, when the composite shielding film is used in an electromagnetic shielding structure, both second conductor 0032 and third conductor 0033 can be connected to a ground frame, thereby grounding both the first and second conductive layers via the ground frame.

[0087] The conductive structure 003 may be implemented in many other ways, which are not listed one by one in the embodiments of the present application.

[0088] In the embodiment of the present application, the conductive structure 003 can be made of any conductive material (such as conductive adhesive, metal, conductive inorganic material, etc.). In the embodiment of the present application, the conductive structure 003 is made of conductive adhesive as an example. For example, the first conductor 0031, the second conductor 0032, and the third conductor 0033 can all be made of conductive adhesive.

[0089] Optionally, the thickness of the first conductive layer 001 and / or the second conductive layer 002 ranges from 1 micron to 100 microns. This thickness range may or may not include 1 micron. This thickness range may or may not include 100 microns. Assuming that the thickness of the first conductive layer 001 and / or the second conductive layer 002 is Y, then 1 micron ≤ Y ≤ 100 microns, or 1 micron < Y ≤ 100 microns, or 1 micron ≤ Y < 100 microns, or 1 micron < Y < 100 microns.

[0090] For example, the thickness of the first conductive layer 001 can be 1 micron, and the thickness of the second conductive layer 002 can be 10 microns; or, the thickness of the first conductive layer 001 can be 10 microns, and the thickness of the second conductive layer 002 can be 10 microns; or, the thickness of the first conductive layer 001 can be 50 microns, and the thickness of the second conductive layer 002 can be 40 microns; or, the thickness of the first conductive layer 001 can be 100 microns, and the thickness of the second conductive layer 002 can be 100 microns; or, the thickness of the first conductive layer 001 can be 40 microns, and the thickness of the second conductive layer 002 can be 50 microns.

[0091] The thickness range of the first conductive layer 001 and the second conductive layer 002 may not be 1 micron to 100 microns, and this embodiment of the present application does not limit this.

[0092] Optionally, the thickness of the composite shielding film (the distance between the surface of the first conductive layer 001 facing away from the second conductive layer 002 and the surface of the second conductive layer 002 facing away from the first conductive layer 001) can be less than 150 microns, for example, less than 100 microns. Of course, the thickness of the composite shielding film can also be greater than or equal to 150 microns.

[0093] The shielding cover in the related art is made of nickel silver and is approximately 150 microns thick. If the composite shielding film in the present application is less than 150 microns thick, then the composite shielding film provided in the embodiments of the present application is thinner than the nickel silver shielding cover in the related art. When this composite shielding film is used as the shielding cover in an electromagnetic shielding structure, the thickness of the entire electromagnetic shielding structure is reduced, which helps reduce the volume of the electromagnetic shielding structure.

[0094] Optionally, please continue to refer to Figure 1 or Figure 3, the composite shielding membrane also includes: a first insulating layer 004 and a second insulating layer 005. The first insulating layer 004 is located between the first conductive layer 001 and the second conductive layer 002, and is used to separate the first conductive layer 001 and the second conductive layer 002. The second insulating layer 005 is located on the side of the second conductive layer 002 away from the first conductive layer 001, and is used to insulate the second conductive layer 002 from the electromagnetic wave signal source when the composite shielding membrane is used in the electromagnetic shielding structure. When the composite shielding membrane is used in the electromagnetic shielding structure, the second insulating layer 005 and the electromagnetic wave signal source can be in contact with or spaced from each other, and this embodiment of the present application is not limited to this. The composite shielding membrane provided in the embodiment of the present application may also not include one or more of the first insulating layer 004 and the second insulating layer 005, and this embodiment of the present application is not limited to this.

[0095] In addition, in the embodiment of the present application, the side of the second insulating layer 005 away from the first conductive layer 001 is taken as an example to be flush with the side of the conductive structure 003 away from the first conductive layer 001. It can be understood that the side of the conductive structure 003 away from the first conductive layer 001 may also protrude from the side of the second insulating layer 005 away from the first conductive layer 001.

[0096] For example, if in the composite shielding film shown in FIG1 , the side of the conductive structure 003 away from the first conductive layer 001 protrudes beyond the side of the second insulating layer 005 away from the first conductive layer 001 , the structure of the composite shielding film may be as shown in FIG7 .

[0097] If in the composite shielding film shown in FIG. 4 , the side of the conductive structure 003 away from the first conductive layer 001 protrudes beyond the side of the second insulating layer 005 away from the first conductive layer 001 , the structure of the composite shielding film may be as shown in FIG. 8 .

[0098] If in the composite shielding film shown in FIG6 , the side of the conductive structure 003 away from the first conductive layer 001 protrudes beyond the side of the second insulating layer 005 away from the first conductive layer 001 , the structure of the composite shielding film may be as shown in FIG9 .

[0099] It is understood that the composite shielding film may also not include the first insulating layer 004 and / or the second insulating layer 005, and this embodiment of the present application is not limited thereto. In this case, the first conductive layer 001 and the second conductive layer 002 are still spaced apart from each other. When the composite shielding film is used in an electromagnetic shielding structure, the second conductive layer 002 is also spaced apart from the electromagnetic wave signal source.

[0100] Furthermore, in the embodiments of the present application, the material of the first conductive layer 001 and the second conductive layer 002 can be any conductive material, such as a carbon material, an organic material, a metallic material, or a non-metallic material. The material of the first insulating layer 004 and the second insulating layer 005 can be any insulating material, such as an organic material, a non-metallic material, etc. Carbon materials, organic materials, and non-metallic materials are generally light in weight, thus enabling the composite shielding film to be lightweight. The material of the first conductive layer 001 and the material of the second conductive layer 002 can be the same or different, and the material of the first insulating layer 004 and the material of the second insulating layer 005 can be the same or different.

[0101] Optionally, the thermal conductivity of the first conductive layer 001 ranges from 1 watt per meter per Kelvin to 400 watts per meter per Kelvin; and / or the thermal conductivity of the second conductive layer 002 is greater than or equal to 10 watts per meter per Kelvin. When the thermal conductivity of the first conductive layer 001 ranges from 1 watt per meter per Kelvin to 400 watts per meter per Kelvin, the material of the first conductive layer 001 can be a conductive material such as a conductive polymer, carbon nanotubes, graphene, or MXenes (a novel material with a two-dimensional layered structure of transition metal carbon / nitrides). When the thermal conductivity of the second conductive layer 002 is greater than or equal to 10 watts per meter per Kelvin, the material of the second conductive layer 002 can be a conductive material such as a conductive polymer, carbon nanotubes, graphene, MXenes, or metal foil. When the thermal conductivity of the first conductive layer 001 ranges from 1 watt per meter per Kelvin to 400 watts per meter per Kelvin, the first conductive layer 001 exhibits good thermal conductivity. When the thermal conductivity of the second conductive layer 002 is greater than or equal to 10 watts per meter per Kelvin, the second conductive layer 002 exhibits good thermal conductivity. This increases the probability that the composite shielding film will exhibit good thermal conductivity, which, when used as a shielding cover, facilitates heat dissipation from electromagnetic wave signal sources.

[0102] It is understandable that the thermal conductivity of the first conductive layer 001 may not be in the range of 1 watt per meter per Kelvin to 400 watts per meter per Kelvin; the thermal conductivity of the second conductive layer 002 may also be less than 10 watts per meter per Kelvin, which is not limited in the embodiment of the present application.

[0103] The above embodiments all use a composite shielding film comprising a single second conductive layer 002 as an example. Alternatively, the composite shielding film may include multiple second conductive layers 002; these multiple second conductive layers 002 are spaced apart and arranged in a plane parallel to the first conductive layer 001. Each of the multiple second conductive layers 002 can refer to the second conductive layer 002 described in the previous embodiments, and will not be further described in this embodiment.

[0104] For example, if the composite shielding film shown in Figure 1 includes multiple second conductive layers 002, the structure of the composite shielding film may be as shown in Figure 10 or Figure 11. Figure 10 takes the composite shielding film including two second conductive layers 002 as an example, and Figure 11 takes the composite shielding film including three second conductive layers 002 as an example.

[0105] If the composite shielding film shown in FIG. 4 includes a plurality of second conductive layers 002 , the structure of the composite shielding film may be as shown in FIG. 12 .

[0106] It is understandable that the composite shielding film including the plurality of second conductive layers 002 may also be different from the composite shielding films shown in FIG. 10 , FIG. 11 and FIG. 12 , and this embodiment of the present application does not limit this.

[0107] Based on the composite shielding film provided in the embodiment of the present application, the embodiment of the present application also provides an electromagnetic shielding structure including the composite shielding film. For example, Figure 13 is a schematic diagram of an electromagnetic shielding structure provided in the embodiment of the present application. As shown in Figure 13, the electromagnetic shielding structure includes: a substrate 01, a grounding frame 02, an electromagnetic wave signal source 03 and a composite shielding film. The composite shielding film can be any one of the composite shielding films provided in the aforementioned embodiments (such as the composite shielding films shown in Figures 1, 4, 6, 7, 8, 9, 10, 11 or 12, and the composite shielding film shown in Figure 4 is taken as an example in Figure 13). For example, when the electromagnetic shielding structure includes the composite shielding film shown in Figure 1, the schematic diagram of the electromagnetic shielding structure is shown in Figure 14.

[0108] The substrate 01 may include a plurality of substrate insulating layers and at least one substrate conductive layer sandwiched between the substrate insulating layers. The substrate may be a printed circuit board (PCB).

[0109] Referring to FIG. 13 or FIG. 14 , ground frame 02 is grounded. Ground frame 02 is located on the target surface of substrate 01 and surrounds target area M on the target surface. Ground frame 02 can be electrically connected to a grounded conductive layer of the substrate to achieve grounding of ground frame 02. Of course, ground frame 02 can also be grounded by other means, such as by connecting the ground frame to a ground trace on the target surface of the substrate, but this embodiment of the present application is not limited thereto.

[0110] The composite shielding film is located on the side of the grounding frame 02 away from the substrate 01, and the conductive structure 003 in the composite shielding film is connected to the side of the grounding frame 02 away from the substrate 01; the second conductive layer 002 in the composite shielding film is located between the first conductive layer 001 and the grounding frame 02; the above-mentioned target area M on the reference plane C is located within the orthographic projection area Q4 of the second conductive layer 002 on the reference plane C; the electromagnetic wave signal source 03 is located between the substrate 01 and the composite shielding film, and is located within the target area M, and is insulated from both the grounding frame 02 and the composite shielding film.

[0111] As can be seen, ground frame 02 and electromagnetic wave signal source 03 are both located on the target surface of substrate 01, wherein electromagnetic wave signal source 03 is located within the target area of ​​the target surface, and ground frame 02 surrounds the target area. Furthermore, ground frame 02 and electromagnetic wave signal source 03 are spaced apart from each other. A composite shielding film covers the side of ground frame 02 and electromagnetic wave signal source 03 that is away from substrate 01. Furthermore, second conductive layer 002 in the composite shielding film is closer to substrate 01 than first conductive layer 001. Conductive structure 003 in the composite shielding film is connected to the side of ground frame 02 that is away from substrate 01, thereby grounding both first conductive layer 001 and second conductive layer 002.

[0112] In the embodiment of the present application, both the first conductive layer 001 and the second conductive layer 002 are grounded, forming a loop. Furthermore, the conductivity of the first conductive layer 001 ranges from 2000 S / m to 80,000 S / m, while the conductivity of the second conductive layer 002 is greater than or equal to 1000 S / m. In this case, a portion of the electromagnetic wave signal emitted by the electromagnetic wave signal source will be shielded at the ground frame 02 and prevented from being transmitted outside the ground frame 02. Another portion of the electromagnetic wave signal will be transmitted to the first conductive layer 001 and / or the second conductive layer 002. Subsequently, these electromagnetic wave signals will be substantially completely dissipated on the first conductive layer 001 under the action of the first and second conductive layers 001 and 002. Thus, electromagnetic wave signals not shielded at the ground frame 02 will not be transmitted outside the electromagnetic shielding structure. Thus, the ground frame 02 and the composite shielding film can shield the electromagnetic wave signal emitted by the electromagnetic wave signal source 03.

[0113] Optionally, the composite shielding film in the above embodiment may include one or more second conductive layers. Accordingly, the target surface has one or more target areas, and the electromagnetic shielding structure includes one or more electromagnetic wave signal sources.

[0114] For example, when the composite shielding film includes multiple second conductive layers 002, the target surface of the substrate 01 has multiple target areas M, and the electromagnetic shielding structure includes: multiple electromagnetic wave signal sources 03. The multiple target areas M correspond one-to-one with the multiple second conductive layers 002, and the orthographic projection areas of the target areas M on the reference plane C are located within the orthographic projection areas of the corresponding second conductive layers 002 on the reference plane C; the multiple target areas M correspond one-to-one with the multiple electromagnetic wave signal sources 03, and the electromagnetic wave signal sources 03 are located within the corresponding target areas M. In this case, the ground frame 02 surrounds each of the multiple target areas M. The ground frame 02 can have multiple hollow areas corresponding one-to-one with the multiple target areas M, and each target area M is located within the corresponding hollow area. Optionally, the orthographic projection areas of the target areas M on the reference plane can overlap with the orthographic projection areas of the hollow areas on the reference plane.

[0115] When the composite shielding film includes multiple second conductive layers 002, a portion of the electromagnetic wave signals emitted by the electromagnetic wave signal source 03 corresponding to each second conductive layer 002 are shielded at the ground frame 02. The remaining portion of the electromagnetic wave signals is transmitted to the first conductive layer 001 or the second conductive layer 002, and is substantially completely dissipated at the first conductive layer 001 due to the interaction between the first conductive layer 001 and the second conductive layer 002. Thus, when the composite shielding film includes multiple second conductive layers 002, the ground frame 02 and the composite shielding film are capable of shielding the electromagnetic wave signals emitted by the multiple electromagnetic wave signal sources 03 corresponding to the multiple second conductive layers 002.

[0116] It can be understood that each electromagnetic wave signal source 03 among the multiple electromagnetic wave signal sources 03 can be one or more devices that can emit electromagnetic wave signals. These devices can be integrated or distributed independently of each other. These devices can be connected to each other or not connected to each other. This embodiment of the present application does not limit this.

[0117] Furthermore, the ground frame 02 in the embodiment of the present application may be a closed frame or not. For example, when the ground frame 02 is not closed, the ground frame 02 has at least one opening in the extension direction of the substrate 01 (parallel to the substrate 01) that connects the target area M and the outside of the ground frame 02.

[0118] For example, assuming that the closed grounding frame 02 is as shown in Figure 15, the structure of the unclosed grounding frame 02 can be as shown in Figure 16, and the grounding frame 02 has multiple openings K connecting the target area M and the outside of the grounding frame 02 in the extension direction of the substrate 01 (such as the direction parallel to the paper surface in Figure 16).

[0119] When the ground frame 02 has the aforementioned opening, the area on the target surface of the substrate 01 where the opening is located can be used to accommodate other structures (such as chips, circuits, etc.) in addition to the ground frame 02, thereby increasing the usable area of ​​the target surface of the substrate 01. Furthermore, although the ground frame 02 has an opening, under the action of the composite shielding film, electromagnetic wave signals that are not shielded at the ground frame 02 are essentially transmitted to the first conductive layer 001 and / or the second conductive layer 002 of the composite shielding film, and are not significantly transmitted from the opening to the outside of the electromagnetic shielding structure. It can be seen that the opening of the ground frame 02 does not significantly affect the electromagnetic shielding function of the electromagnetic shielding structure. If the shielding cover is made of nickel silver as used in the related art, then when the ground frame 02 has the aforementioned opening, a large amount of electromagnetic wave signals will be transmitted from the opening to the outside of the electromagnetic shielding structure, thereby failing to achieve the electromagnetic shielding function of the electromagnetic shielding structure.

[0120] Optionally, the ratio of the sum of the areas of the orthographic projections of all openings of ground frame 02 on the reference plane to the sum of the areas of the orthographic projections of the portions of ground frame 02 excluding the openings on the reference plane can be 2 / 3, 1 / 4, 3 / 2, etc. Thus, the opening area of ​​a ground frame having openings can be 40%, 20%, 60%, etc., of the total area of ​​the enclosed ground frame. The embodiment of this application does not limit the size of the opening area.

[0121] As can be seen from the above, the electromagnetic shielding structure provided in the embodiments of the present application has multiple implementation methods. Six examples of electromagnetic shielding structures are given below.

[0122] Example 1: A composite shielding film comprises a first conductive layer, one or more second conductive layers, a conductive structure, a first insulating layer, and a second insulating layer. The conductivity of the first conductive layer is 2000 S / m, and the thickness of the first conductive layer is 1 micron; the conductivity of the second conductive layer is 1000 S / m, and the thickness of the second conductive layer is 10 microns. The conductive structure connects the first conductive layer and the second conductive layer, and the conductive structure is connected to the grounding frame to ground the first conductive layer and the second conductive layer. The second conductive layer is located on the side of the first conductive layer close to the substrate. The ratio of the sum of the areas of the orthographic projections of the areas where all openings of the grounding frame are located on the reference plane to the sum of the areas of the orthographic projections of the parts of the grounding frame other than the openings on the reference plane is 2 / 3.

[0123] Example 2: Based on Example 1, the conductivity of the first conductive layer is changed to 2000 S / m, the thickness of the first conductive layer is changed to 10 microns, and for electromagnetic wave signals between 300 MHz and 10 GHz, the relative complex permeabilities of the first and second conductive layers are both 1.

[0124] Example 3: Based on Example 1, the conductivity of the first conductive layer is changed to 10000 S / m, the thickness of the first conductive layer is changed to 50 microns, and the conductivity of the second conductive layer is changed to 1*10 6 S / m, the thickness of the second conductive layer becomes 40 microns.

[0125] Example 4: Based on Example 1, the conductivity of the first conductive layer is changed to 80000 S / m, the thickness of the first conductive layer is changed to 100 microns, and the conductivity of the second conductive layer is changed to 4*10 6 S / m, and the thickness of the second conductive layer becomes 100 microns.

[0126] Example 5: Based on Example 1, the conductivity of the first conductive layer is changed to 20000 S / m, the thickness of the first conductive layer is changed to 40 microns, and the conductivity of the second conductive layer is changed to 3*10 6 S / m, the thickness of the second conductive layer becomes 50 microns. Moreover, for electromagnetic wave signals of 300 MHz to 10 GHz, the relative complex permeabilities of the first conductive layer and the second conductive layer are both 10.

[0127] Example 6: Based on Example 1, the conductivity of the first conductive layer is changed to 20000 S / m, the thickness of the first conductive layer is changed to 40 microns, and the conductivity of the second conductive layer is changed to 3*10 6 S / m, the thickness of the second conductive layer becomes 50 microns. For electromagnetic wave signals of 300 MHz to 10 GHz, the relative complex permeabilities of the first conductive layer and the second conductive layer are both 10. In addition, the grounding frame is a closed frame without an opening.

[0128] Testing the six examples above yielded the test results shown in Table 1 below. During this test, the interference strength of the electromagnetic wave signal source on the antenna was measured, using a global positioning system (GPS) module and a wireless (Wi-Fi) module as examples. This interference strength can reflect the effectiveness of electromagnetic shielding. Stronger interference strength indicates more electromagnetic wave signal leakage and poorer electromagnetic shielding effectiveness; weaker interference strength indicates less electromagnetic wave signal leakage and better electromagnetic shielding effectiveness.

[0129] Table 1

[0130] It can be seen from Table 1 that the test results of the electromagnetic shielding structures of the above six examples are all good, and the signal test conclusions of these six examples are all passed, indicating that the electromagnetic shielding effects of the electromagnetic shielding structures provided by these six examples are all good.

[0131] Furthermore, the electromagnetic shielding structures provided by these six examples are all relatively lightweight, achieving a weight reduction compared to the electromagnetic shielding structure in the related art, where the shielding cover is made of 150-micron-thick nickel silver. The weight reduction ratio of the electromagnetic shielding structure provided by each example compared to the weight reduction ratio of the electromagnetic shielding structure provided by the shielding cover is shown in Table 1. In other words, the weight reduction ratio = (weight of the electromagnetic shielding structure provided by the shielding cover using 150-micron-thick nickel silver - weight of the electromagnetic shielding structure provided by the example) / weight of the electromagnetic shielding structure provided by the shielding cover using 150-micron-thick nickel silver.

[0132] Furthermore, in Examples 1 to 5, the ground frame all had openings, while Example 6 did not. Therefore, the usable area on the substrate in Examples 1 to 5 was larger than that in Example 6, and Examples 1 to 5 all achieved a 40% area gain. However, Example 6 did not achieve an area gain, achieving a zero area gain. Furthermore, a comparison of Examples 1 to 6 shows that whether the ground frame had openings did not affect the electromagnetic shielding effectiveness of the electromagnetic shielding structure.

[0133] Furthermore, the embodiments of the present application also provide the following eight comparative examples for comparison with the above six examples.

[0134] In comparative example 1, the shielding cover adopts an electromagnetic shielding structure made of nickel silver with a thickness of 150 microns. The shielding cover is connected to a grounding frame, and the grounding frame has no opening.

[0135] Comparative Example 2: Based on Example 1, the conductive structure does not ground the first conductive layer and the second conductive layer.

[0136] In comparative example 3, the shielding cover adopts an electromagnetic shielding structure made of nickel silver with a thickness of 100 microns. The shielding cover is connected to a grounding frame, and the grounding frame has an opening.

[0137] Comparative Example 4: A carbon-based film with a thickness of 100 microns and an electrical conductivity of 10,000 S / m is used as the shielding cover. The shielding cover is connected to a grounding frame, and the grounding frame has an opening.

[0138] Comparative Example 5: A carbon-based film with a thickness of 100 microns and an electrical conductivity of 20,000 S / m is used as the shielding cover. The shielding cover is connected to a grounding frame, and the grounding frame has an opening.

[0139] Comparative Example 6: Based on Example 1, the conductivity of the first conductive layer is changed to 500 S / m. It can be seen that the conductivity of the first conductive layer is not in the range of 2000 S / m to 80000 S / m.

[0140] Comparative Example 7: Based on Example 1, the conductivity of the first conductive layer is changed to 100,000 S / m. It can be seen that the conductivity of the first conductive layer is not in the range of 2,000 S / m to 80,000 S / m.

[0141] Comparative Example 8: Based on Example 1, the conductivity of the first conductive layer is changed to 10,000 S / m, and the conductivity of the second conductive layer is changed to 500 S / m. It can be seen that the conductivity of the second conductive layer is not greater than or equal to 1,000 S / m.

[0142] The eight comparative examples are tested to obtain the test results shown in Table 2. During the test, the electromagnetic wave signal sources are respectively taken as GPS module and WIFI module as examples to test the interference intensity of the electromagnetic wave signal source on the antenna.

[0143] Table 2

[0144] As can be seen from Table 2, of the eight comparative examples, only Comparative Example 1 passed the signal test, while Comparative Examples 2 through 8 all failed. This indicates that the electromagnetic shielding structures provided by Comparative Examples 2 through 8 have poor electromagnetic shielding effectiveness. Although Comparative Example 1 passed the signal test, it did not achieve any weight or area reduction benefits.

[0145] Combining Examples 1 to 5 and Comparative Example 2, it can be seen that the conductive structure grounding both the first and second conductive layers has a significant effect. In Examples 1 to 5, the conductive structure grounds both the first and second conductive layers, allowing the electromagnetic wave signal to be effectively conducted between the first and second conductive layers, thereby facilitating the electromagnetic wave signal to enter the first conductive layer for loss, and the signal test passes. Because the conductive structure in Comparative Example 2 does not ground the first and second conductive layers, the electromagnetic wave signal cannot be effectively conducted between the first and second conductive layers, and thus the electromagnetic wave signal cannot enter the first conductive layer for loss, and the signal test fails.

[0146] Combining Examples 1 to 5 and Comparative Examples 3 to 5, it can be seen that when the shielding cover uses the composite shielding film provided in the embodiments of the present application, even if the ground frame has an opening, the electromagnetic wave signal will not easily leak through the opening, and thus the signal test passes. When the shielding cover is made of a single material, if the ground frame has an opening, the electromagnetic wave signal is more likely to leak through the opening, causing the signal test to fail.

[0147] In combination with Examples 1 to 5, and Comparative Examples 6 to 8, it can be seen that when the conductivity of the first conductive layer is in the range of 2000S / m to 80000S / m, and the conductivity of the second conductive layer is greater than or equal to 1000S / m, effective shielding can be achieved. When the conductivity of the first conductive layer exceeds the range of 2000S / m to 80000S / m, or the conductivity of the second conductive layer is lower than 1000S / m, effective shielding cannot be achieved. Among them, in Comparative Example 6, the conductivity of the first conductive layer is lower than 2000S / m. In this case, the first conductive layer cannot effectively attenuate the electromagnetic wave signal that has converged between the first conductive layer and the second conductive layer, thereby causing the electromagnetic wave signal to leak out. In Comparative Example 7, the conductivity of the first conductive layer is higher than 80000S / m, so that the signal that has converged between the first conductive layer and the second conductive layer is reflected out of the electromagnetic shielding structure by the first conductive layer, thereby causing the electromagnetic wave signal to leak out. In Comparative Example 8, the conductivity of the second conductive layer is lower than 1000 S / m, and the second conductive layer cannot effectively reflect the electromagnetic wave signal, resulting in the electromagnetic wave signal not being able to converge between the first conductive layer and the second conductive layer, thereby causing the electromagnetic signal to leak.

[0148] It should be noted that the dimensions of some or all structures in the accompanying drawings may be exaggerated for clarity, and the dimensions, size relationships, proportions, shapes, etc. of these structures shown in the drawings can be adjusted as needed. For example, the ground frame shown in FIG15 is a regular rectangular frame, but in some cases, the ground frame can also be an irregular frame. For another example, the central area in FIG2, FIG3, and FIG5 is a rectangular shape, but in some cases, the shape of the central area can also be irregular rather than rectangular, and the corresponding edge area surrounding the central area can also be irregular.

[0149] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance. The term "at least one" refers to one or more, and "plurality" refers to two or more, unless otherwise expressly defined. The term "and / or" in this application is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the related objects before and after are in an "or" relationship.

[0150] In this application, "greater than" can be replaced by "greater than or equal to", and "less than" can be replaced by "less than or equal to". Accordingly, "greater than or equal to" can be replaced by "greater than", and "less than or equal to" can be replaced by "less than".

[0151] In the corresponding embodiments provided in this application, it should be understood that the disclosed structures can be implemented through other configurations. For example, the embodiments described above are merely illustrative.

[0152] The above are merely optional embodiments of the present application, but the scope of protection of the present application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and such modifications or substitutions should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A composite shielding film, characterized in that, Comprising: A first conductive layer, a second conductive layer, and a conductive structure; The first conductive layer and the second conductive layer are opposite and spaced apart from each other. The positive projection area of the second conductive layer on a reference plane parallel to the first conductive layer is located within the positive projection area of the first conductive layer on the reference plane. The conductivity of the first conductive layer ranges from 2 kiloSiemens per meter to 80 kiloSiemens per meter, and the conductivity of the second conductive layer is greater than or equal to 1 kiloSiemens per meter; The conductive structure connects the first conductive layer and the second conductive layer and is used to ground the first conductive layer and the second conductive layer.

2. The composite shielding film according to claim 1, wherein The conductivity of the first conductive layer ranges from 20 kiloSiemens per meter to 80 kiloSiemens per meter, or from 30 kiloSiemens per meter to 50 kiloSiemens per meter.

3. The composite shielding film according to claim 1 or 2, characterized in that The conductivity of the second conductive layer is greater than the conductivity of the first conductive layer.

4. The composite shielding film according to claim 3, characterized in that, The conductivity of the second conductive layer is greater than 100 kiloSiemens per meter, or the conductivity of the second conductive layer is greater than 500 kiloSiemens per meter, or the conductivity range of the second conductive layer is greater than 1 million Siemens per meter.

5. The composite shielding film according to any one of claims 1 to 4, characterized in that The conductive structure includes: a first conductor and a second conductor; The first conductor is located between the first conductive layer and the second conductive layer and connects the first conductive layer and the second conductive layer; The second conductor is located on the side of the second conductive layer away from the first conductive layer and connects the second conductive layer. The second conductor is used for grounding.

6. The composite shielding film according to claim 5, wherein The conductive structure further includes: a third conductor; The third conductor is located on the side of the first conductive layer close to the second conductive layer, and the positive projection area of the third conductor on the reference plane is located outside the positive projection area of the second conductive layer on the reference plane; The third conductor connects the first conductive layer and the third conductor is used for grounding.

7. The composite shielding film according to any one of claims 1 to 6, characterized in that, The material of the conductive structure includes conductive glue.

8. The composite shielding film according to any one of claims 1 to 7, characterized in that, For electromagnetic wave signals from 300 MHz to 10 GHz, the relative complex permeability of the first conductive layer and / or the second conductive layer is greater than or equal to 1.

9. The composite shielding film according to any one of claims 1 to 8, characterized in that, The thickness range of the first conductive layer and / or the second conductive layer is from 1 micron to 100 microns.

10. The composite shielding film according to any one of claims 1 to 9, characterized in that, The thermal conductivity range of the first conductive layer is from 1 watt per meter per Kelvin to 400 watts per meter per Kelvin; and / or the thermal conductivity of the second conductive layer is greater than or equal to 10 watts per meter per Kelvin.

11. The composite shielding film according to any one of claims 1 to 10, characterized in that, The composite shielding film includes: a plurality of the second conductive layers; The plurality of the second conductive layers are spaced apart from each other in a plane parallel to the first conductive layer.

12. The composite shielding film according to any one of claims 1 to 11, characterized in that, The composite shielding film further includes: a first insulating layer and / or a second insulating layer; The first insulating layer is located between the first conductive layer and the second conductive layer; The second insulating layer is located on the side of the second conductive layer away from the first conductive layer.

13. An electromagnetic shielding structure, characterized in that, Comprising: A substrate, a grounding frame, an electromagnetic wave signal source, and the composite shielding film according to any one of claims 1 to 12; The grounding frame is grounded. The grounding frame is located on a target surface of the substrate and surrounds a target area of the target surface; The composite shielding film is located on a side of the grounding frame away from the substrate, and a conductive structure in the composite shielding film is connected to the side of the grounding frame away from the substrate; a second conductive layer in the composite shielding film is located between the first conductive layer and the grounding frame; A positive projection area of the target area on the reference plane is located within a positive projection area of the second conductive layer on the reference plane; The electromagnetic wave signal source is located between the substrate and the composite shielding film, within the target area, and is insulated from both the grounding frame and the composite shielding film.

14. The electromagnetic shielding structure according to claim 13, characterized in that, The composite shielding film includes: a plurality of the second conductive layers, the target surface has a plurality of the target areas, and the electromagnetic shielding structure includes a plurality of the electromagnetic wave signal sources; A plurality of the target areas correspond to a plurality of the second conductive layers one by one, and a positive projection area of the target area on the reference plane is located within a positive projection area of the corresponding second conductive layer on the reference plane; A plurality of the target areas correspond to a plurality of the electromagnetic wave signal sources one by one, and the electromagnetic wave signal source is located within the corresponding target area.

15. The electromagnetic shielding structure according to claim 13 or 14, characterized in that, The grounding frame has at least one opening that communicates the target area and the outside of the grounding frame in an extending direction of the substrate.

16. An electronic device, characterized in that, Comprising: The electromagnetic shielding structure according to any one of claims 13 to 15.

17. The electronic device according to claim 16, characterized in that, The electronic device is a terminal device.

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